Pr3+ as a sensitiser of red Eu3+ luminescence in K5Li2GdF10:Pr3+, Eu3+ upon VUV–UV excitation

Abstract The intensity ratio of luminescence originating from the 5D0 level to that originating from the 5D1 level of Eu3+ in the K5Li2GdF10:Pr, Eu system is found to be considerably greater upon the indirect excitation of 5d levels of Pr3+ or Gd3+ multiplets than in the case of direct excitation into Eu3+ levels. The generalized Yokota–Tanimoto model was used to explain the behaviour of decay curves of 3P0 luminescence and to determine the kinetic micro-parameters: CDA related to cross-relaxation, and D related to the energy migration probabilities. The Pr–Eu “critical radius” was calculated to be in the range 13.9–15.3 A.